Title: Modeling riverbank erosion - An analytical approach

Abstract

Rivers all over the world have unique features of their own. Rigorous and meticulous experimentation may help quantify the riverbank erosion to a great extent. However, results of field studies have their own limitations due to the uniqueness of the river. Therefore, application of the result obtained out of thorough investigation pertaining to a typical riverbank often comes out to be a difficult proposition for others. A general approach to the phenomenon is the need of the hour for estimation of the magnitude of erosion. A particle on a bank is subjected to a number of forces of considerable significance. A force analysis involving forces like cohesive force, viscous force, pore water pressure force, gravity force, seepage force and so on, leads to determination of the escape velocity of the particle. Also, there is a variation of water level in the river that necessitates use of the principle of conservation of angular momentum. This velocity is a pre-requisite to find out volumetric bank erosion rate. A planar model called “Truncated Pyramid Model” may successfully be used towards that direction. The essence of the model lies in the concept of collective stability of a group of particles. The escape velocity is arrived at considering the dynamic equilibrium. The results, when validated against some already published results, prove the efficacy of the model. Thus, it opens the door for further investigation with more degrees of freedom.